DESCRIPTION (From the Applicant?s Abstract): The goals of the application are to identify genes and mutations that cause inherited cataracts, and to develop a canine model to study the molecular aspects of inherited congenital cataracts in humans. Both a candidate gene approach and a genome-wide scan will be used. Cataracts are the leading cause of blindness worldwide. The most common cataracts occur in the elderly. However, the molecular etiology of these senile cataracts is not well understood. Congenital cataracts are less prevalent in the population yet approximately 1/3 of them are inherited. As a result, the study of congenital cataracts has contributed more to our understanding of the molecular bases of inherited cataracts. Genotypic and phenotypic heterogeneity make direct linkage studies and the identification of cataract genes problematic in man. As a results, animal models have been used to circumvent this problem. Although the mouse model has been used extensively, advances in canine genetics have produced the foundation on which to study inherited diseases in the canine model as a complementary species. For example, the development of the canine genetic, RH, and cytogenetic maps along with the creation of a BAC library, have provided the necessary tools for using he dog as a model to study genetic diseases including cataracts.